This invention relates to conditioning of seeds including cereal grains, pulses (peas, beans, lentils and other leguminous crops) and other edible seeds such as sunflower or safflower seeds, rapeseeds, etc. In particular, the invention relates to conditioning of such seeds prior to rolling, i.e., passing the seeds through rollers to flatten them, usually to make them more digestible and/or palatable. As used herein, the term "rolling" includes the conventional variations thereof, e.g. flaking or crimping of the seeds.
In foods or animal feeds containing such seeds, microorganisms can cause heating, caking or dusting, and also impart unpleasant odors or flavors. Further, the presence of certain microbial species can lead to the formation of toxic metabolites known as mycotoxins, including aflatoxins, ochratoxins, rubratoxins, citrinin and others.
Generally, it is necessary that edible seeds be conditioned prior to rolling by increasing their moisture level, preferably softening the seeds so that proper rolling, flaking and/or crimping will occur rather than crushing or powdering. For this purpose, steam conditioning is often utilized, the seeds being exposed to steam within a conditioning chamber through which the seeds flow prior to rolling. After rolling, the seeds are normally dried and cooled but retain a finite moisture level and are thus vulnerable to growth of microorganisms such as molds, yeasts, and/or bacteria.
To inhibit the growth of microorganisms, it has been known to treat edible seeds, e.g., by a spray application following rolling, with various feed preservatives including potassium sorbate, sorbic acid, propionic acid and calcium propionate. Sorbic acid and the sorbates are highly efficacious for this purpose.
When subjected to rolling, such edible seeds are prone to the formation of fines resulting from comminution of seed structures. As such structures break and separate under mechanical stress, the fines tend to accumulate in processing and handling facilities or are otherwise lost. Thus, for example, grain dust accumulates in and around grain handling equipment including conveyors, augers, etc. Such dust constitutes a safety hazard, being combustible and even explosive.
When feeds containing such fines are fed to animals, they may cause respiratory problems, especially in horses which are commonly fed flaked grain. In cattle parlors, fines objectionably accumulate in feeding containers.
To the feed grain producer, such fines constitute an economic loss. In small scale operations, fines are irretrievably lost. Other processors may blend fines into lesser quality feeds, e.g., in pelleting operations, to partially reduce such losses. In any event, it is typical for fines to constitute for the producer a loss of 5 percent or more of the processed grain or other edible seeds.